Field of the Invention
The present invention is directed generally to systems and methods for improving a tube bending machine, and to systems and methods for efficiently changing tooling for such machines.
Description of the Related Art
Pipe (or tube) bending is the generally-used term for metal forming processes used to permanently form pipes or tubing. The resulting pipes or tubes may be used in a variety of applications, including but not limited to, automotive exhaust systems and household water systems. There are multiple types of procedures for bending tubes, including form-bound procedures. Form-bound bending procedures like “press bending” or “rotary draw bending” are used to form the work piece into the shape of a die. Straight tube stock can be formed using a bending machine to create a variety of single or multiple bends and to shape the piece into the desired form. These processes can be used to form complex shapes out of different types of ductile metal tubing. Generally, round stock tubes are used in tube bending. However, square and rectangular tubes and pipes may also be bent to meet job specifications. Other factors involved in the tube bending process are the wall thickness of the tubes and the tooling and lubricants needed by the tubes.
To bend a tube in a rotary-draw bender, it is first positioned inside the bender. It is then locked in place by closing of the clamp die onto the bend die. With the tube in place, the bend die and clamp die then rotate around as one piece, bending the tube around the bend die, with the pressure die maintaining pressure against the wiper, and moving along in the axial direction at a prescribed percent boost. The rotation is continued until a desired tube bend angle is reached. To control the axial tube motion, the pressure die applies axial force to the tube either through friction (between pressure die and tube) or through an optional boost block, which pushes against the back of the tube during bending. A boost clamp may also be used to compliment the friction and boost block. The boost clamp is a mechanical clamping device that grips the tube to the pressure die when friction is not enough or the end of the tube cannot be accessed.
The role of the pressure die is two-fold. First, it must exert sufficient clamping pressure by pushing the tube against the wiper die (inclined at a small rake angle) to prevent wrinkling on the inside bend of the tube, and secondly it must control the axial movement of the back of the tube feeding into the bend. In many applications, tube bending requires precise alignment between a bend die, follower die, clamp die, and wiper die.
To change the various dies for different be sized tubing, general practice has been to individually remove each of the dies and reassemble a new die set onto a bending machine, which is time-consuming and results in considerable downtime.